Represent enums with regular structs; no more alignment-breaking casts.

src/test/run-pass/enum-alignment.rs

@@ -0,0 +1,26 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn addr_of<T>(ptr: &T) -> uint {
+    let ptr = ptr::addr_of(ptr);
+    unsafe { ptr as uint }
+}
+
+fn is_aligned<T>(ptr: &T) -> bool {
+    (addr_of(ptr) % sys::min_align_of::<T>()) == 0
+}
+
+pub fn main() {
+    let x = Some(0u64);
+    match x {
+        None => fail!(),
+        Some(ref y) => fail_unless!(is_aligned(y))
+    }
+}